Talk is not working (most of the time)

i have installed Nextcloud on my Server and everything is working fine, but talk have some errors.
I also installed a Turnserver.
With the talk app or in the browser i can chat with everyone, but when i videocall somebody it doesent work for most of the time.
For example i call smartphone 1 with my laptop connected via hotspot of smartphone 2, and its working. But when i call smartphone 1 with smartphone 2 its connected but there is no video and no microphone. And thats weird because its the same internetconnetction as if i call with pc to smrtphone 1.
Does anyone of you has an answer for that?